Method for identifying extender text table of electronic program guide in digital tv

ABSTRACT

A digital television (DTV) receiver and a decoding method are discussed. According to an embodiment, the DTV receiver includes: a receiving unit for receiving a digital broadcasting signal including a plurality of extended text tables (ETTs) that appear in transport stream packets having common PID values, each ETT comprising a section header and a message body, wherein the section header contains a table identification extension field that serves to establish uniqueness of each ETT, and wherein the message body includes an extended text message (ETM) which provides detailed descriptions of a virtual channel or an event associated with each ETT; and a program and system information protocol (PSIP) decoder for detecting the table identification extension field to determine uniqueness of each ETT and detecting at least one pertinent ETT from the plurality of ETTs using the determined uniqueness of each ETT.

This application is a Continuation of co-pending application Ser. No.11/704,922 filed on Feb. 12, 2007; which is a Continuation of co-pendingapplication Ser. No. 11/062,429 filed on Feb. 23, 2005 (now U.S. Pat.No. 7,246,365 B2 issued on Jul. 17, 2007); which is a Continuation ofco-pending application Ser. No. 09/760,840, filed on Jan. 17, 2001 (nowU.S. Pat. No. 6,918,133 issued on Jul. 12, 2005); and for which priorityis claimed under 35 U.S.C. §120; and this application claims priority ofApplication No. P2000-2065 filed in the Republic of Korea on Jan. 17,2000 under 35 U.S.C. §119. The entire contents of all are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital broadcasting, and moreparticularly, to a method for identifying extender text tables of anelectronic program guide in a digital television.

2. Description of the Related Art

Generally, video and audio streams are compressed as digital informationwhile system and program information are compressed in accordance with aprogram and system information protocol (PSIP) to provide digitalbroadcasting. Here, program information is decoded from data other thanthe video and audio information, and displayed on a screen for a userthrough an electronic program guide (EPG). The EPG and systeminformation are combined into the PSIP and as the ATSC standard forground wave and cable digital broadcasting, the PSIP provides a varietyof information on programs by parsing messages encoded through a movingpicture experts group (MPEG-2, ISO/IEC 13818-1 system) method (December1997 document A/65).

The PSIP includes a plurality of tables to transmit and receive A/V datagenerated in MPEG-2 video and AC-3 audio formats, and to transmitinformation and programs on channels of broadcasting stations.Accordingly, the PSIP enables a primary function of providing A/Vservices for broadcast programs of selected channels as well as asecondary function of providing guide services, i.e. EPG, for thebroadcast programs. Particularly, information such as information onchannels for channel-selecting and packet identification digits (PID)for A/V reception is transmitted through a virtual channel table (VCT),while EPG information on broadcast programs for the channels istransmitted through an event information table (EIT).

The EIT is information regarding the events of virtual channels andincludes a title and start time of each event. Here, an event istypically a TV program. Also, the PSIP can transmit at least four and atmost one hundred twenty eight EITs in the format of EIT-k, where eachEIT provides an event information of a specific time band.

The PSIP further includes a system time table (STT) which provides timeinformation; a rating region table (RRT) which transmits information onregions and rating organizations, i.e. ranking programs; an extendertext table (ETT) which further explains channels and broadcast programs;and a master guide table (MGT) which manages the version and PID of eachtable. These tables are transmitted by data structures called sections.Namely, a section is the elementary unit of each table and one or moresection(s) are combined to form a complete table. Accordingly, tofacilitate user interface, the EPG representing information on programsto be broadcasted on a digital television (DTV) has a variety of formatsdepending on the section(s) defining a table.

A widely used format of the EPG is by using a Gemstar table. In suchformat, an ETT which contains detailed information on an event, i.e. abroadcast program, can have event information corresponding to a unit ofthree hours. Also, each event information is represented and identifiedby an index based on a chronological order of EIT-1, EIT-1, . . . ,EIT-127. Thus, an ETT is mapped with each corresponding EIT, i.e. eventinformation corresponding to EIT-0 is mapped with ETT-0, eventinformation corresponding to EIT-1 is mapped with ETT-1, . . . , andevent information corresponding to EIT-127 is mapped with ETT-127. Here,an EIT can also represent information on events of up to three hours ina single section, where each event has an event_id field for identifyingthe event and an ETM_location field for displaying whether an ETT whichcontains detailed information on the event is present.

Furthermore, each section of the ETT comprises an ETM_id representing anevent or a channel as well as detailed text information on the event orchannel. The sections of tables used in PSIP have syntax types asfollows. table_id 8 bits section_syntax indicator 1 bitsprivate_indicator 1 bits reserved 2 bits section_length 12 bits table_id_extension 16 bits  reserved 2 bits version_number 5 bitscurrent_next_indicator 1 bits section_number 8 bits last_section_number8 bits protocol_number 8 bits actual_table_data * CRC_32 32 bit 

The table sections, as listed above, can be for section headers oftables which have common rules of composition or for section bodies oftables which have different contents depending on the objective of atable. Here, a section header has basic information such as table_id,table_id_extension, version_number, and section_number, which identifiesa section in the section header. Specific field value(s) based on suchbasic information which identify section(s) within the section headercan be used to extract certain section(s). Namely, the section(s) withbasic information which match the specific field value(s) can beextracted. This process is known as section filtering.

General formats of EIT and ETT are shown in FIG. 1. As shown, a sectionEIT-0 within an EIT includes a plurality of events, where each event isdistinguished or identified by the event_id and the ETM_locationindicates whether an ETT exists for the identified event. Also, anETM_id within each ETT section is represented by asource_id+event_id+1sb and indicates the event to which the ETT sectioncorresponds. For example, in the ETM_id of ‘XX . . . X00000000000011XX’shown in FIG. 1, the underlined portion represents an event mapped witha corresponding event_id. In other words, an ETT-0 has a link with acorresponding event through the ETM_id in the section body.

However, information in the section header of the ETT-0 such as thetable_id, the table_id_extension, the section_number, and thelast_section_number includes the same value of ‘00000000000011’regardless of the section. Namely, each section has the same sectionheader, excluding the version field. Thus, to process an ETT, requiredcontents of the ETT are randomly extracted through a section headerfiltering according to a sequential process as shown in FIG. 2.

Referring to FIG. 2, an ETT section filter is first set (S1) and the ETTsection-outs, which have been received, are detected (S2). All receivedETT sections are then input (S3) and the input ETT sections are parsed(S4). Next, an ETM_id is detected depending on the result obtained fromparsing the ETT sections (S5) and the detected ETM_id is compared withan event_id to determine if the values are identical (S6). If thedetected ETM_id is identical to the event_id, the ETM_id is stored as atext message (S8) and the processing of the ETT ends. Otherwise, thecorresponding section is dumped (S7) and a next ETM_id is detected andcompared to the event_id by repeating the above process.

However, a method for identifying ETTs of an EPG of a DTV according tothe related art has the following problems.

First, because the section headers of ETT sections are basicallyidentical, a general section filtering cannot be conducted. Thus, allsections of, for example, ETT-0 corresponding to an EIT-0 are receivedand parsed to select a required ETT-0 section, resulting in a repeatedprocessing of an ETT section. Second, upon receiving a command toidentify whether the contents of an ETT-0 section has been changed whena version number is altered, the entire ETT-0 sections must be parsed todetect an ETM_id. Third, if ETT sections are not the same version, asection filtering based on the version cannot be performed. In otherwords, the method, in which different sections of the ETT-0 have thesame section header, fails to meet the system standard of the movingpicture experts group (MPEG) as well as to perform a section filteringof sections using the header.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to address at leastthe problems and disadvantages of the related art.

Another object of the present invention is to provide a more efficientdigital broadcasting.

Another object of the present invention is to provide a more efficientmethod for identifying ETTs.

A further object of the present invention is to provide a method forprocessing ETT section header to identify ETTs.

A still further object of the present invention is to identify ETTs byprocessing ETT sections in the same manner as other tables of PSIP.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

To achieve the objects and in accordance with the purposes of theinvention, as embodied and broadly described herein, a method foridentifying ETTs of an EPG in a DTV according to an aspect of thepresent invention includes inputting an event_id in a table_id_extensionwithin ETT sections such that the ETT sections are identified at areceiving or a transmitting party without parsing the ETT sections.Preferably, the ETM_location values within the ETT sections aredistinguishably represented such that it is possible to determinewhether the ETT is transmitted from a same channel or from anotherchannel being broadcasted. Also, ETT section headers among the ETTsections is preferably represented to determine whether the ETT sectionincludes detailed information for channels or for events.

According to another aspect, the present invention is directed to adigital television (DTV) receiver, comprising: a receiving unit forreceiving a digital broadcasting signal including a plurality ofextended text tables (ETTs) that appear in transport stream packetshaving common PID values, each ETT comprising a section header and amessage body, wherein the section header contains a table identificationextension field that serves to establish uniqueness of each ETT, andwherein the message body includes an extended text message (ETM) whichprovides detailed descriptions of a virtual channel or an eventassociated with each ETT; and a program and system information protocol(PSIP) decoder for detecting the table identification extension field todetermine uniqueness of each ETT and detecting at least one pertinentETT from the plurality of ETTs using the determined uniqueness of eachETT.

According to another aspect, the present invention is directed to adigital television (DTV) receiver, comprising: a receiving unit forreceiving a digital broadcasting signal including a plurality of eventextended text tables (ETTs) that appear in transport stream packetshaving common PID values, each event ETT comprising a section header anda message body, the section header containing a table identificationextension field, the message body containing an extended text messagewhich provides detailed descriptions of an event associated with eachevent ETT, wherein the table identification extension field defines anevent identification (ID) of the event to establish uniqueness of eachevent ETT; and a decoder for detecting the event ID of the event todetermine uniqueness of each event ETT and detecting at least onepertinent event ETT from the plurality of ETTs using the detected eventID.

According to another aspect, the present invention is directed to amethod of decoding a broadcast signal in a digital television (DTV)receiver, the method comprising: receiving a digital broadcast signalincluding a plurality of extended text tables (ETTs) that appear intransport stream packets having common PID values, each ETT comprising asection header and a message body, the section header containing a tableidentification extension field that serves to establish uniqueness ofeach ETT, the message body containing an extended text message (ETM)which provides detailed descriptions of a virtual channel or an eventassociated with each ETT; detecting the table identification extensionfield to determine uniqueness of each ETT; and detecting at least onepertinent ETT from the plurality of ETTs using the determined uniquenessof each ETT.

According to another aspect, the present invention provides a method ofdecoding a broadcast signal in a digital television (DTV) receiver, themethod comprising: receiving a digital broadcast signal including aplurality of event extended text tables (ETTs) that appear in transportstream packets having common PID values, each event ETT comprising asection header and a message body, the section header containing a tableidentification extension field, the message body containing an extendedtext message which provides detailed descriptions of an event associatedwith each event ETT, wherein the table identification extension fielddefines an event identification (ID) of the event to establishuniqueness of each event ETT; detecting the event ID of the event todetermine uniqueness of each event ETT; and detecting at least onepertinent event ETT from the plurality of ETTs using the detected eventID.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 shows an EIT and ETT in the related art;

FIG. 2 is a flowchart of a method for processing ETT sections in therelated art; and

FIG. 3 is a flowchart of a method for processing ETT sections accordingto an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. In the following description, well-known functions orconstructions will not be described in detail.

According to the present invention, ETT sections are generallyidentified by a section header through a table_id_extension. Namely, anevent_id is input into the table_id_extension to represent acorresponding event. Thus, a general section filtering method can beused to process only the section(s) necessary at a receiver.

A method for identifying ETTs of an EPG in a DTV according to thepresent invention will next be described in detail, where Table 1 belowshows the syntax types of table sections used in the PSIP. TABLE 1 Bitstream syntax for the ETT in A/65(PSIP document)extended_text_table_section ( ) { table_id 8 0xC7section_syntax_indicator 1 ‘1’ private_indicator 1 ‘1’ reserved 2 ‘11’section_length 12 uimsbf table_id_extension 16 0x0000 uimsbf reserved 2‘11’ version_number 5 uimsbf current_next_indicator 1 ‘1’ section_number8 0x00 last_section_number 8 0x00 protocol_version 8 uimsbf ETM_id 32uimsbf extended_text_message( ) var CRC_32 32 rpchof }

The present invention distinguishes and identifies the ETT sections byinserting an event_id into a table_id_extension, where thetable_id_extension is commonly used in ETT header sections with a fixedvalue of 0x00. Particularly, a table_id_extension is composed of 16 bitsand according to the present invention, 14 bits of the 16 bits representan event_id and residual 2 bits remain. One of the residual 2 bits maybe used for identifying whether a value of an ETM_location is 0x01 or0x02, and the other residual bit may be used for identifying whether theETT section is related to channels or to events.

For example, an ETM_location value of 0x01 may indicate that the ETT istransmitted from the same channel as the EIT. In such case, anETM_location value of 0x02 would indicate that the ETT is transmittedfrom a channel actually being broadcasted. Accordingly, whether an ETTsection is related to channels, which are currently being transmitted,or related to events can be determined by values of 0x01 or 0x02represented in the table_id_extension. Also, the other bit containsinformation on whether an ETT section has detailed information onchannels or on events, and can be distinguished through the ETT sectionheader.

For example, a table_id_extension may be composed as shown in Table 2below. TABLE 2 table_id_extension (16 bits) value correspondingevent/channel to ETM-location event-id 0/1 0/1 XX XXXX XXXX XXXX

By inputting a value, which can distinguish and identify an ETT section,into the table_id_extension as shown in Table 2, a section filtering canbe executed and thus, required ETT section(s) can be selectivelyreceived. For example, if an event_id requires detailed information onevents represented in ‘00 0000 0000 1111,’ the event_id selectivelyreceives ETT section(s) having a table_id of 0xCC and table_id-extensionhaving values corresponding to ‘00 0000 0000 1111.’

Referring to FIG. 3, in processing an ETT according to the presentinvention, an ETT section filter is initially set (S10). The ETTsection-outs are then detected (S20), and pertinent ETT section(s)is(are) filtered and detected (S30) using the event_id inserted in thetable_id_extension of the ETT sections. Next, the detected ETTsection(s) is(are) parsed (S40) and the parsed section(s) is(are) storedas a text message (S50).

Accordingly, in the present invention, an ETT of EPG is generated byinserting an event_id in a table_id_extension of each ETT section headerto identifies an event to which an ETT section corresponds. Also, anETM_location value may be inserted in the table_id_extension todistinguish whether an ETT section is transmitted from the same channelas EIT, and/or a value may be inserted in the table_id_extension todistinguish whether detailed information in an ETT section is forchannels or for events.

Similarly, a method for identifying ETTs of an EPG comprises insertingan event_id in a table_id_extension of each ETT sections beforetransmitting the ETT sections to a receiver; and section filtering, atthe receiver, the received ETT sections based upon the event_id toidentify an ETT section. Namely, an ETT section can be identified bysetting an ETT section filter; detecting ETT section-outs; sectionfiltering and detecting at least one pertinent ETT section using theevent_id in the table_id_extension of each ETT sections; parsing thedetected at least one ETT section; and storing each parsed ETT sectionas a text message.

Furthermore, if the table_id_extension is available for sectionidentification, a version processing according to the section can beperformed. Specifically, when contents of a section changes, aversion_number is accordingly altered to represent the change. As aresult, a transmitter can determine which ETT section is to betransmitted with changed contents by referring to a section header, andcan produce and use a section filter. Thus, if the contents of a sectionamong the ETT sections are changed, a transmitter can change the versionof section(s) for section(s) with changed contents because the sectionsare distinguishable. Similarly, a receiver can filter and receive thesection(s) with values corresponding to the changed version. Namely, ETTsections can be filtered at the receiver by detecting ETT sections withvalues corresponding to a specific version.

As described above, a method for identifying ETTs of an EPG in a DTVaccording to the present invention has the following advantages. First,the method can filter ETT sections without receiving all sections and/orrepeatedly filtering the unnecessary sections. Second, the method mayuse a value which can identify each ETT section and allow a control ofthe version. Third, the method maintains an existing section headerwhile employs a table_id_extension field of 0x00, i.e. the same value asin the section header, thereby being compatible with existing receivers.

The foregoing embodiments are merely exemplary and are not to beconstrued as limiting the present invention. The present teachings canbe readily applied to other types of apparatuses. The description of thepresent invention is intended to be illustrative, and not to limit thescope of the claims. Many alternatives, modifications, and variationswill be apparent to those skilled in the art.

1. A method of processing a broadcast signal in a digital television(DTV) receiver, the method comprising: receiving a broadcast signalcomprising a plurality of extended text tables (ETTs) that appear intransport stream packets having common PID values, wherein each ETTcomprises a section header including a table identification (ID)extension value such that separate ETT instances appearing in thetransport stream packets have a unique table ID extension value, whereineach ETT further comprises a section body including an extended textmessage (ETM) which provides detailed descriptions of a virtual channelor an event associated with each ETT; and detecting at least onepertinent ETT by section-filtering the plurality of ETTs using the tableID extension field included in the section header of each ETT.
 2. Themethod of claim 1, further comprising: parsing the detected ETT; andstoring an extended text message (ETM) included in the parsed ETT. 3.The method of claim 1, wherein the table ID extension value indicates anevent identification (ID) to which each ETT corresponds.
 4. The methodof claim 1, wherein the section header further includes a valueindicating whether each ETT is transmitted from a same channel as acorresponding event information table (EIT).
 5. The method of claim 1,wherein the section header further includes a value identifying each ETTas one of an event and channel ETT.
 6. The method of claim 1, whereinthe section header further includes a value indicating whether each ETTis transferred from a same channel as a corresponding event informationtable (EIT), and a value identifying each ETT as being one of an eventand channel ETT.